1. Field of the Invention
This invention relates to valves and more particularly to rotary spool valves.
2. Description of the Prior Art
Spool valves for utilization with hydraulic control systems including the use of four-way valves are well-known in the prior art. The inventor of the present invention has received five prior U.S. Patents in this area, namely U.S. Pat. No. 3,774,504 for a Sliding Spool Valve; No. 4,027,697 for a Rotary Valve; No. 4,124,038 for a Multiway Hydraulic Valve; No. 4,184,513 for a Multiple Three and/or Two-way Valve; and No. 4,177,834 for a Rotary Four-way Tandem Center Valve. These patents and the references cited therein are related to the field wherein the present invention resides. Also considered relevant in the prior art are U.S. Pat. No. 3,213,881 to J. B. Findlay et al for a Directional Control Valve and U.S. Pat. No. 2,749,941 to L. E. Gardiner for a Rotary Control Valve.